And of course, you will also need to give out your phone number, and be sitting near the phone all the time, and be ready to receive phone calls for activation, for people who use your program on computers without internet access.Well, if its just a cd key then all they have to do is give their friend the cd key too, it needs soem online verification. An easy way is to associate teh hard drive serial number with teh cd key and only let it change once every 30 days or so. For this you need to have soem authentication server program runnign all the time.